Hii, My Period Date Is 15th And I Had Unprotected

Hii, my period date is 15th and I had unprotected sex on 22nd. I took an I pill on 24th. Tody its 3 weeks my periods have got delayed.i tuk pregnancy kit tests twice with a gap of 3 dayz at home, both were negative. But still no periods. By November 15 th I would have missed my period for amonth.do I see a doctor?